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UNIT-4, Linux Operating System, The architecture of the Linux operating system:system The Linux operating system basically, works on 4 layers. See the below diagram, shows the layers of the Linux operating system, architecture., , 1.Kernel layer:- The kernel is one of the core section of a Linux operating system. It is, responsible for each of the major actions of the Linux OS. This operating system contains, distinct types of modules and cooperates with underlying hardware directly. The kernel, facilitates, itates required abstraction for hiding details of low-level, low level hardware or application, programs to the system. There are some of the important kernel types which are mentioned, below:, o Monolithic Kernel., o Micro kernels., o Exo kernels., o Hybrid kernels., 2.Shell layer:- It is an interface among the kernel and user. It can afford the services of, kernel. It can take commands through the user and runs the functions of the kernel. It is the, interface, terface which takes input from users, u, and sends instructions to the kernel, also takes the, output from kernel and sends the result back to output shell. Shell is hiding complexity of, kernel's functions from users. The shell is available in distinct, ct types of operating systems., These operating systems are categorized into two different types, which are the graphical, shells and command-line, line shells., shells, The graphical line shells facilitate the graphical user interface, while the command line shells, facilitate the command line interface. Thus, both of these shells implement operations, operations., However, the graphical user interface shells work slower as compared to the command, command-line, interface shells.

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3.Application and Utility layer:- It provides the functionalities of an operating system to the, user. It is responsible for doing specialized level and individual activities. These are the, utility programs which run on Shell. This can be any application like your web browser,, media player, text editor etc., A Linux-based system will typically arrive with such a set of established Unix-like utility, services. These were all generally basic functions used in day-to-day operating system usage, and also specific devices and applications. This is usually software that was published and, released under the open-source license by the GNU Project. Therefore the software can be, openly downloaded, updated, and redistributed to all. Some instances would have been the, commands that allow users to share and modify files and folders, generate data as well as do, jobs such as backup files., 4.Hardware layer:- Linux operating system contains a hardware layer that consists of, several peripheral devices. These devices are attached to the System. Some examples of, peripheral devices are Hard disk drive, RAM, Motherboard, CPU, Mouse, Keyboard etc., XX##XX